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reedomneck
Associate III
January 24, 2026
Question

IAP over SPI stm32u5

  • January 24, 2026
  • 2 replies
  • 197 views

 

I need support to get IAP over SPI.

I've esp connected to my stm32u5 over SPI. Stm is slave and ESP is master.

 

For stm I've created project using stmcube by entering MCU part number.

Now here my question is

1. Do I need to develop bootloader code to achieve this.

2. How do I customise bootloader code.

3. STM boot pin is connected to ESP. do I need to control this?

4. Hwi do I adjust my memory or linker file

2 replies

TDK
Super User
January 24, 2026

You can use the system SPI bootloader if the pins you have connected are compatible. See AN2606 for compatible pins and AN4286 for the protocol.

Introduction to system memory boot mode on STM32 MCUs - Application note

SPI protocol used in the STM32 bootloader - Application note

 

There are several IAP examples out there you could use. Here is one from ST:

How to use the ST Open Bootloader for STM32 Microc... - STMicroelectronics Community

Solved: How can I develop a Bootloader for a STM32H745 (Du... - STMicroelectronics Community

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reedomneck
Associate III
March 13, 2026

@TDK Thanks for sharing this resources.
So I should get started with openbootloader. For STM32U535 is this available?

TDK
Super User
March 13, 2026

There's an example for the U585. Implementation for U535 should be similar if not identical.

Screenshot 2026-03-13 143904.png

 

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